The present invention relates to a non-magnetic substrate for a magnetic head and to a magnetic head having a high wear resistance.
A magnetic head is used for magnetically recording and reproducing an information signal for a magnetic recording medium such as a magnetic tape.
Development of high density magnetic recording requires a magnetic recording medium of an increased coercive force and a magnetic head using a magnetic core of an increased saturated magnetic flux density corresponding to the increased coercive force. Metallic magnetic materials having a high magnetic permeability and a low coercive force, for example, Fe-Si-Al alloy which is so called "Sendust" (trademark) and a certain amorphous alloy, have a high saturated magnetic flux density in comparison with the known ferrite. Therefore, magnetic heads have been developed which use those metallic magnetic materials for magnetic cores.
A typical one of such magnetic heads comprises a magnetic film as a magnetic core having a magnetic gap, reinforcing members supporting the magnetic film core, and a coil or coils wound on the magnetic film core and the reinforcing members. The magnetic head of this type will be referred to as a superposed type head in the following description.
In a known magnetic head of the the superposed type, the magnetic core film is made of "Sendust" alloy (which is an FeSiAl alloy or an alloy of FeSiAl added with Cr, Ru, Ti and the like) sputtered on a non-magnetic substrate as one of the reinforcing members (Japanese Patent publication No. 2-48965, Reference I).
Japanese Patent Application No. 2-23686 (Reference II) discloses another head of the type wherein the magnetic core film is made of a sputtered alloy film which essentially consists of Fe, N, and M (M is at least one selected from a group of Ta, Hf, Nb, Zr, V and Ti). The alloy has a saturated magnetic flux density higher than the "Sendust" alloy.
Generally, the magnetic head, in detail, the magnetic core and the reinforcing members are worn by sliding contact with the magnetic recording medium during magnetic recording and reproducing. Accordingly, it is important for actual use of those magnetic heads disclosed in References I and II to grade up the wear resistance of the heads.
In the magnetic head disclosed in Reference I, MnO-NiO substrate is used for the reinforcing members. In order to improve the wear resistance, Japanese Patent Application No. 2-264320 (Reference III) proposes to use CaO-TiO.sub.2 -NiO substrate having a relatively high wear resistance for the reinforcing members. However, the magnetic head using the substrate of CaO-TiO.sub.2 -NiO is insufficient in the recording and reproducing properties. Further, the higher wear resistance is desired for the magnetic head.